the roof caves in

the roof caves in

The situation collapses; everything goes wrong. Typically used in the past tense. I was living paycheck to paycheck and getting by OK, but then the roof caved in. I lost my job, and then my car and my house.
See also: cave, roof
Farlex Dictionary of Idioms.

the roof falls in

a disaster occurs; everything goes wrong.
See also: fall, roof
Farlex Partner Idioms Dictionary
See also:
  • the roof falls in
  • big ticket
  • big-ticket
  • under the table
  • be just before you're generous
  • generous
  • deduck
  • out of the hole
  • knew it was coming
  • know (something) is coming